Abstract:

The deployment of horizontal well groups for shale oil development represents an innovative approach to fracturing, addressing the constraints observed in single horizontal wells. This study focuses on the fracturing dynamics within groups of horizontal wells, where the interplay of multiple wells and artificial fractures introduces complex variations in stress around the fractures and the in-situ stress distribution between wells. Such complexities significantly influence the morphology of fracture propagation. A comprehensive investigation into the stress field dynamics under various fracturing methods in horizontal well groups was conducted using a hydraulic fracturing numerical model. This research is crucial for manipulating fracture morphology and enhancing fracture complexity. The study systematically explored the stress distribution during the shale oil reservoir fracturing reconstruction, analyzed fracture morphologies, and quantitatively assessed the fracturing outcomes. Key findings include: ① Synchronous fracturing effectively alters inter-well ground stress, with the staggered pattern inducing a 24% higher stress compared to the opposite pattern, thereby influencing the direction and reversal of ground stress under identical well spacing. ② Staggered layout exhibit superior shape and fracturing effects than those under the opposite layout, significantly increasing the length, width, surface area, and volume of fractures by 4.6% and 21.1%, respectively. ③ Zipper fracturing enhances fracture dimensions more effectively than synchronous fracturing, increasing the total surface area and volume of the fractures by 1.3% and 0.1%, respectively.

Key words: horizontal well group fracturing, hydraulic fracturing, stress field, synchronous fracturing, zipper fracturing